SREL Reprint #2767




Anthropogenic Activities Producing Sink Habitats for Amphibians in the Local Landscape: A Case Study of Lethal and Sublethal Effects of Coal Combustion Residues in the Aquatic Environment

Christopher L. Rowe and William A. Hopkins

Introduction: When examining the issue of global amphibian population declines, it is important to consider amphibian population responses to environmental changes operating at local scales, influencing specific populations or habitats and perhaps contributing to larger-scale phenomena (e.g., Rowe, Hopkins, Coffman, Congdon 2001). Localized effects on habitat quality, when considered in toto, may result in a landscape that is characterized by regions of low environmental quality and subsequent negative effects on amphibian populations. It is thus useful to invoke a "source versus sink" perspective on the landscape as a whole (sensu Pulliam 1988), recognizing that a landscape visualized on the basis of habitat quality will be interrupted in places by regions of low quality associated with localized anthropogenic activities such as contaminant release. Thus, habitat quality within a landscape will change abruptly from areas of relatively high quality (source habitats in which recruitment occurs) to areas of relatively low quality (sink habitats in which immigrants experience recruitment failures). While adult amphibians may continue to be present in sink habitats due to migration from nearby areas, their contribution to the entire population is limited due to reduced reproductive success mediated by reduced reproductive output and/or high embryonic or larval mortality. In such a way, environmental contamination may produce regions in the landscape (reproductive "black holes") into which adults from local populations make repeated, losing investments in reproduction. Not all contaminant releases to the environment will result in severe enough reductions in habitat quality such that amphibian population sinks form in the landscape. The specific effects of contaminants on amphibians (e.g., their ability to influence recruitment or performance of recruits), the spatial and temporal nature of contaminant inputs, and the location of the contamination events within the landscape will determine whether local amphibian populations may be at risk of contaminant effects...

SREL Reprint #2767

Rowe, C. L. and W. A. Hopkins. 2003. Anthropogenic activities producing sink habitats for amphibians in the local landscape: A case study of lethal and sublethal effects of coal combustion residues in the aquatic environment. p. 271-282 In: G. Linder, S. Krest and D. Sparling (Eds.). Amphibian Decline: An Integrated Analysis of Multiple Stressor Effects. Society of Environmental Toxicology and Chemistry.

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